Millennials feel more stress than older generations, study says

With decades ahead of them in the job market, more than half of millennials stay awake at night chewing over all manner of worries, according to a study.

Those 18- to 33-yeas-olds actually stress out more than older generations, the American Psychological Assn. concluded in its new study. Slightly more than 50% said that overwhelming worries disrupted their sleep in the past month.

A dour economy is top of mind for young people, with work and job stability sending their stress levels soaring. And no wonder -- their unemployment rate is 13.1%, well above the overall nation's 7.8%. A recent survey of 2010 college graduates found nearly half were in jobs that didn't require a university diploma.

"Many of these young people have come out of college or graduate school with horrendous student debt into a job market where there are not very many jobs," Katherine Nordal, the psychological group's executive director of professional practice, told NBC News. "This has put their life plans, probably, on hiatus."

Nearly 40% of millennials said their stress shot up in the last year, compared with 33% of baby boomers and 29% of those 67 and older.

Perhaps reflecting their relative inexperience with the working world, the study found young people were more likely to react to stress with anger or annoyance.